3 February 2021

3 minute read

Europe

The survey involved 10 farms in the South West of England and was undertaken by Molecare Farm Vets, in partnership with DSM. The results showed that:

• 90 percent of fresh cows were deficient in vitamin E and 75 percent deficient in beta carotene.
• Half of dry cows were deficient in both antioxidants.
• 30 percent of cows were still deficient in both antioxidants, three weeks after calving,

The data is in-line with existing research findings which highlights an increased risk of vitamin E and beta carotene deficiency in house systems feeding "yellow" diets made up of more than 50 percent maize, straw and wholecrop. Compared to "green," grass-based diets, these forages tend to be low in key antioxidants. This was underlined by the fact the only farm feeding a "green," grass silage based ration, was not deficient in beta carotene at any point.

The fact all of the farms feeding "yellow" diets were already supplementing with vitamin E, suggests inclusion rates need to be raised on these feeding systems. Although beta carotene is not typically supplemented in the UK, the data also suggests it could be worth providing cows with this antioxidant when grass inclusion rates are reduced.

Vet Andy Adler of Molecare Farm Vets, says the correct supply of vitamin E and beta carotene is vital considering the role they play in fertility. “Antioxidants are involved in protecting the body’s cells from detrimental chemicals that are produced in response to normal insult and trauma seen around calving,” he explains. “If these chemicals aren’t removed, they can have a negative impact on bodily tissues, and particularly those involved in fertility, such as the growing oocyte (egg).”

Providing cows with antioxidants helps counteract these detrimental chemicals and protects the growing oocyte. With the oocyte starting to develop 100 days before a cow comes into heat, making sure she has sufficient levels during the dry and transition period is essential.

Jamie Gibbons, Mineral Supplements Technical Manager for Mole Valley Farmers, says this is underlined by the fact a high proportion of freshly calved cows were found to be deficient.

“This shows it’s worth increasing supplementation around calving to raise blood levels and help prepare the cow for increased demand when she calves,” he says. “Supplementation with key antioxidants - including vitamin E & Beta carotene - during the dry period and up until cows are served will give the best protection for the developing oocyte so it is ready for fertilisation.”

Current guidelines suggest feeding up to 1,000mg per cow per day of beta carotene pre-calving through early lactation and up to 4,000 IU per cow per day of vitamin E for close-up dry cows.

Jamie adds: “The National Research Council (NRC) is currently reviewing recommendations for antioxidants and is likely to increase recommended levels in dairy diets. Our survey suggests this is the right move. Fertility is multi-factorial, but optimal antioxidant status is one thing that contributes to better conception rates and more cows in-calf."